Weak magnetic fields once exposed humans to radiation. People adapted with shelter, clothing, and mineral protection.
When we first got together, we wondered whether our unconventional project, linking space weather and human behavior, could actually bridge such a vast disciplinary divide. Now, two years on, we believe the payoffs – personal, professional and scientific – were well worth the initial discomfort.
Our collaboration, which culminated in a recent paper in the journal Science Advances, began with a single question: What happened to life on Earth when the planet’s magnetic field nearly collapsed roughly 41,000 years ago?
Under normal conditions, Earth’s magnetic field behaves like a stable dipole, similar to a bar magnet. During the Laschamps Excursion, however, it broke apart into several weaker poles scattered across the globe. This fragmentation weakened the magnetosphere, Earth’s natural shield that normally blocks much of the solar wind and harmful ultraviolet radiation from reaching the surface.
With the magnetosphere compromised, models suggest that a variety of near-Earth effects would have occurred. Auroras, which today are usually confined to the polar region , likely appeared much closer to the equator, and the planet was exposed to significantly higher levels of solar radiation than we experience now.
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